Recently, to enhance the visibility for a vehicle, research on a vehicle including a camera module system provided with a plurality of cameras installed on the outside of the vehicle to enable a driver or a passenger in the vehicle to check outside conditions of the vehicle has been carried out.
Moreover, such a vehicle is provided with a screen for displaying images received from the plurality of cameras on the interior of the vehicle through an optical module. In this regard, development of related devices for assisting in driving of the vehicle and improving convenience in use has become appreciably more active.
Meanwhile, unlike the configuration of an optical module embedded in a cowl top cover or a dashboard of a vehicle, in the case of a subminiature projection optical module mounted in an A-filler or B-filler, there is a problem of low visibility because the size of an image projected onto a screen is small.
Furthermore, with regard to installation of such a subminiature projector, it is not easy to dispose the projector in an interior part of the vehicle and secure a space for configuration of a projection-type optical module for projecting an image having a predetermined size sufficient to provide appropriate visibility.
FIG. 1 illustrates a projection lens unit for a pico-projector according to the conventional technique proposed in Korean Patent Application No. 10-2008-0081806 (hereinafter, referred to as ‘Document 1’). The projection lens unit includes a lens array formed of five sheets, a color synthesizing prism, a cover glass and an image panel.
However, in the case of the configuration of Document 1, it is difficult to provide the projection-type optical module in a confined space of the interior of the vehicle. Moreover, there is still a problem in that it is difficult to project an image onto a wide area having a predetermined size sufficient to provide appropriate visibility.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.